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PC WILL NOT BOOT TO WIN 7 PRO WITH USB PLUGGED IN

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taglaser62:
well... i spoke too soon.
disabling legacy usb support allowed me to boot windows 7 pro with this specific EZB USB devise connected, but stopped mouse & keyboard support for the Acronis Rescue CD at boot which is linux based.
so i continued to go down devcon path.
with devcon.exe in root directory and using cmd i ran devcon.exe disable "@... see attached. ran okay and asked me to reboot.
i rebooted as prompted and had EZB USB unplugged. booted okay.
then i plugged EZB usb into port and ran EZB sw which did not find the EZB hw which is what we wanted to happen.
i also tested to make sure EZB sw saw hw in another port.
i then, leaving the EZB USB connected to the disabled port, rebooted, but windows would not boot.
basically same result as before devcon was run.
help!

[ Invalid Attachment ]
[ Invalid Attachment ]

Shades:
From the images you provided I see you have a PC with an older AMI BIOS. More modern versions of BIOS and/or UEFI allow for much more fine-grained control about which USB connected devices can be disabled at starting the PC.

Mouses and keyboards that are connected through USB have no need to use for the latest incarnation of the USB protocol and still chug along with the lowest version of USB they can get away with (which usually means USB 1.1). That USB standard is more than adequate for those devices, mouses only send relative position data, clicks etc. Even a fast typist cannot type fast enough to saturate the data bandwidth provided by an USB 1.1 port.

The 'USB Legacy' option in your BIOS apparently means that USB 1.1 devices are disabled at boot.

Modern versions of BIOS/UEFI are able to distinct between USB devices and allow keyboard/mouse to be enabled while other USB devices are not.
 
Not sure if there is even a BIOS upgrade for your specific motherboard model available that gives you more fine-grained control over USB devices. Upgrading a BIOS isn't very difficult and doesn't take much time. However, if anything goes wrong during this BIOS upgrade procedure, there is a distinct possibility you brick your computer.

Some older PC's have some kind of backup BIOS chip on their motherboard, but most PC's only come with one of those chips and most are soldered directly on the motherboard.
Mess it up and you can look forward to time-consuming and (very) costly repairs. If you are lucky you can get a new BIOS chip from the manufacturer or you need to hunt for
a similar chip on a spare/(not too) broken motherboard (exact same make and model as the one you have). Replacing the old BIOS chip with the new one requires some expertise as well.

This is the option in the BIOS/UEFI from my 3 year old PC that would resolve your problem.
PC WILL NOT BOOT TO WIN 7 PRO WITH USB PLUGGED IN
Unfortunately your BIOS doesn't seem to have it.

taglaser62:
i just installed the latest AMI bios 2.02 in 6028 SBC.
same boot issues.

with this certain usb device plugged in (EZB USB) then win 7 pro will not boot. part way through windows logo screen it reboots and bios screen comes up.
if i disable legacy usb support in bios the problem disappears, but then my acronis rescue disc (Linux) has no kybd or mouse support.(acronis wants usb legacy support enabled)

tried recommendation to use devcon script to disable port at shutdown and then restart at boot up. i disabled (did not try to automatically re-enable yet) and port was disabled (i checked it by trying to run EZB application), but at boot up with legacy usb support enabled i got same result: windows tries to start and then reboots.

i have either not found bios solution on this SBC or I have not provided the right setting or combination of settings.

other recommendations are less palatable solutions like adding a relay that disconnects power to EZB USB or a device/relay that disconnects the USB connection until after boot up. the issue with this is that there would have to be some way (handshake) of the PC telling the PLC that boot up has occurred so that power or USB connection may be remade and then the PC would have to start the application program that looks for the EZB USB. EZB USB must be connected & powered when EZB application is started. I would consider this if i could get a commercially available handshake between PC & PLC.

i notice other USB settings in 2.02 but again not sure what to set them at.
notably: under chipset\USB config\USB PRECONDITION & XHCI MODE & USB PER PORT DISABLE CONTROL.
Is there something here you would recommend to try?

ami bios & start up manual attached.

Shades:
A cheaper and/or easier project would be to convert your keyboard and/or mouse to the old, but reliable PS/2 port(s) your PC is likely to have...in case you use a wired keyboard and/or mouse. Now you can disable legacy USB in your BIOS, while you have a fully functional keyboard/mouse during the boot procedure.

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